If you're talking solo AoE farming for shit, I just find my demo lock (with DA glyph and Soul Link/Harvest Life talents) to be completely unkillable when wading into packs of shit that I wouldn't even think of doing the same with my mage or priest, and all 3 of them are alts that are geared in crafted blues plus the random epic, like Klaxxi ring and Sha boot.

FnB Immolate, Rain of Fire and FnB Incin spam is retarded. You also get unlimited Ember Taps because of ember regen from all the immolates + RoF. Once everything gets to execute range, tab target shadowburn spam.

Assuming that you reach (or pass) the new AoE-Cap you do 6 million dmg.
With a reasonable amount of haste you need ~12 seconds to do so.
500k dps with 3 globald cooldowns used in 12 seconds.
the best part ist that you still can add your frozen orb every 45 seconds which will increasly damage even further.

Warlock is awesome. Spam aoe, get infinite embers (as destro), be invincible, tag shit instantly so no CR-zoned jerk can steal it.
For my spots where there are a LOT of mobs and they respawn almost immediately it's super effective. Farmed on huntard before that but it was meh, people were stealing mobs from me all the time because i needed to round them up with my mount first.

FnB Immolate, Rain of Fire and FnB Incin spam is retarded. You also get unlimited Ember Taps because of ember regen from all the immolates + RoF. Once everything gets to execute range, tab target shadowburn spam.

Totally this. going apeshit with AoE as destro is not only fun, but it's fast. And as for survivability, Sacrificial pact, glyphed healthstones / embertap, unending resolve and the like will make you almost indestructible.

We can put out pretty much damage on a pack, but then our abilities are on cool down. We also have very little ways to heal ourself while moving.

If you took 10 packs, a Warlock could kill all 10 packs at once and keep moving with no downtime. A mage would kill one pack, then wait for Frost Orb and FB cooldown, kill another pack and so on.

Frost mages used to be way better then they are now at AOE.

In fact, I would argue many classes are now better than we are at AOE farming. Watching a Brewmaster or Bear Druid gather up 20 mobs and destroy them while still remaining at 100 percent HP is far superior to anything a Frost mage can do.

We used to be able to kite, blizzard everything to death. You can't do that anymore.

Icelance with Glyph only hits 2 targets and one at 50 percent of your dmg. It's barely an AOE.

Frostbomb is also, but it's range is awful. If you have a casters in the pack, either the melee or ranged won't get hit by it. It also does less damage the more mobs you have.

Frost also has no other ways to damage an area of enemies outside of Frost Orb, which goes on cooldown. Fire can also not spread it's dots to a huge pack any longer.